In radio communications systems, data is transmitted via electromagnetic waves. The electromagnetic waves are transmitted via antennas, with the carrier frequencies being in the frequency band intended for the respective system. In addition to the requirement to restrict the dimensions of the antenna to fit into the small sizes of the mobile radio transmitting and receiving devices, there is also an increasing requirement for the capability to transmit and receive in multiple different frequency bands, thus, giving the mobile radio devices access to greater bandwidth.
Tunable antennas, therefore, are desirable given the current demand for bandwidth in today's mobile radio designs. Multiple band (e.g., quad-band) antenna design in today's small mobile radio handsets is extremely difficult using the standard inverted F antennas or bent monopole antennas.